Gas-pulsing-based shared precursor distribution system and methods of use

ABSTRACT

Gas distribution apparatus to provide uniform flows of gases from a single source to multiple processing chambers are described. A regulator is positioned at an upstream end of a shared volume having a plurality of downstream ends. A flow controller is positioned at each downstream end of the shared volume, the flow controller comprising an orifice and a fast pulsing valve. Methods of using the gas distribution apparatus and calibrating the flow controllers are also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/664,154, filed Apr. 28, 2018, the entire disclosure of which ishereby incorporated by reference herein.

FIELD

Embodiments of the disclosure generally relate to gas distributionapparatus. More particularly, embodiments of the disclosure relate toapparatus to distribute gas to multiple processing chambers usingpulsing gas flows.

BACKGROUND

Semiconductor device formation is commonly conducted in substrateprocessing platforms containing multiple chambers. In some instances,the purpose of a multi-chamber processing platform or cluster tool is toperform two or more processes on a substrate sequentially in acontrolled environment. In other instances, however, a multiple chamberprocessing platform may only perform a single processing step onsubstrates; the additional chambers are intended to maximize the rate atwhich substrates are processed by the platform. In the latter case, theprocess performed on substrates is typically a batch process, wherein arelatively large number of substrates, e.g. 25 or 50, are processed in agiven chamber simultaneously. Batch processing is especially beneficialfor processes that are too time-consuming to be performed on individualsubstrates in an economically viable manner, such as for atomic layerdeposition (ALD) processes and some chemical vapor deposition (CVD)processes.

During processing, expensive precursor gases are frequently wasted bybeing diverted to the foreline when not in use. Additionally, deliveryhardware for providing precursor flows is expensive and often requires adedicated gas stick for delivering a precursor to each and every waferprocessing station.

Accordingly, there is a need in the art for apparatus and methods touniformly and relatively inexpensively deliver gases to multipleprocessing chamber or process regions.

SUMMARY

One or more embodiments of the disclosure are directed to gasdistribution apparatus comprising a shared volume having an upstream endand a plurality of downstream ends. A pressure gauge is connected to theshared volume. A pressure controller is connected to the upstream end ofthe shared volume. A flow controller is at each of the downstream endsof the shared volume. Each flow controller comprises an orifice and afast pulsing valve.

Additional embodiments of the disclosure are directed to methods ofcalibrating a flow controller comprising a fast pulsing valve and anorifice. The methods comprise opening a pressure controller at anupstream end of a shared volume to pressurize the shared volume. Theshared volume has an upstream end and a plurality of downstream ends andeach downstream end has a flow controller. The pressure controller atthe upstream end is closed to isolate the pressure in the shared volume.The pressure in the shared volume is measured. A fast pulsing valve ofone flow controller is opened a predetermined number of times and thepressure in the shared volume is measured after opening the fast pulsingvalve. The pressure loss in the shared volume per pulse of the fastpulsing valve is determined for that flow controller.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of embodiments ofthe disclosure can be understood in detail, a more particulardescription of embodiments of the disclosure, briefly summarized above,may be had by reference to embodiments, some of which are illustrated inthe appended drawings. It is to be noted, however, that the appendeddrawings illustrate only typical embodiments of this disclosure and aretherefore not to be considered limiting of its scope, for the disclosuremay admit to other equally effective embodiments.

FIG. 1 shows a schematic representation of a gas distribution apparatusin accordance with one or more embodiments of the disclosure;

FIG. 2 shows an expanded view of region II of FIG. 1;

FIG. 3 shows an expanded view of region III of FIG. 1; and

FIG. 4 shows an expanded view of region II of FIG. 1 according to one ormore embodiment of the disclosure.

DETAILED DESCRIPTION

Embodiments of the disclosure provide a substrate processing system forcontinuous substrate deposition to maximize throughput and improveprocessing efficiency. One or more embodiments of the disclosure aredescribed with respect to a spatial atomic layer deposition chamber.

Embodiments of the disclosure provide a new way of distributingprecursors to multiple stations within a wafer processing chamber, andto multiple chambers within a cluster tool for atomic layer deposition(ALD) applications. A shared volume is advantageously used for a singleprecursor distribution to a whole cluster tool or multiple gas outletsof a batch processing chamber. Some embodiments advantageously providegas pulsing technology to ensure accurate and repeatable/reproducibleprecursor delivery to all the stations of all the chambers within acluster tool without any waste of expensive precursors.

Some embodiments of the disclosure advantageously provide apparatus andmethods to minimize wasting of expensive precursors due to divertingprecursor to foreline when not in use. Some embodiments advantageouslyprovide apparatus and methods that minimize high precursor-deliveryhardware costs due to using a dedicated gas stick for delivering aprecursor to each and every wafer processing station of an ALD chamber.

FIG. 1 shows an exemplary embodiment of the disclosure. A gasdistribution apparatus 100 comprising a shared volume 110 to distributegases to multiple processing stations 101. The use of the term“processing stations” refers to any chamber or process region of achamber. For example, the processing stations 101 can be separateprocessing chambers or can be separate process regions of a single batchprocessing chamber. While FIG. 1 is illustrated with three processingstations 101, the skilled artisan will recognize that more or less thanthree processing stations 101 can be connected to the apparatus gasdistribution apparatus 100.

The shared volume 110 has an upstream end 111 and a plurality ofdownstream ends 112. The shared volume 110 of some embodiments, as shownin the Figures, includes one or more of a gas reservoir 120 ordistribution lines. In some embodiments, the shared volume 110 includesan upstream distribution line 130 from the upstream end 111 of theshared volume 110 to the gas reservoir 120. In some embodiments, theshared volume 110 includes a downstream distribution line 140 from thegas reservoir 120 to the plurality of downstream ends 112.

A pressure gauge 150 can be connected to the shared volume 110 tomeasure the pressure between the upstream end 111 and the plurality ofdownstream ends 112. The pressure gauge 150 can be positioned at anypoint between the upstream end 111 and the downstream ends 112. In someembodiments, the pressure gauge 150 is configured to measure thepressure in the gas reservoir. In some embodiments, there is more thanone pressure gauge configured to measure pressure at different points ofthe shared volume 110.

A pressure controller 160 is connected to the upstream end 111 of theshared volume 110. As used in this manner, when a gas flow component isconnected to another gas flow component, there is fluid communicationbetween the components so that there is substantially no interferencewith the gas flow. As shown in the expanded view of region II in FIG. 2,the pressure controller of some embodiments comprises one or more of aregulator 162 or a mass flow controller. The regulator 162 or mass flowcontroller can be any suitable gas regulator or mass flow controllerknown to the skilled artisan. The regulator provides a supply pressure(or input pressure) to the shared volume 110. The regulator 162 can beany mechanical or electrically controlled proportional pressure controlcomponent.

In some embodiments, the pressure controller 160 includes a fast pulsingvalve 164. The fast pulsing valve 164 can be positioned between theregulator 162 and the upstream end 111 of the shared volume 110. In someembodiments, the fast pulsing valve 164 is upstream of the regulator162. The fast pulsing valve 164 can be any valve that can open and/orclose within 50 milliseconds. In some embodiments, the fast pulsingvalve 164 can open and/or close within 40 milliseconds, 30 milliseconds,20 milliseconds or 10 milliseconds. In some embodiments, the fastpulsing valve 164 can open and close within 50, 40, 30, 20 or 10milliseconds. In some embodiments, the fast pulsing valve 164 is a valvethat is either fully open or fully closed. In some embodiments, the fastpulsing valve 164 is a variable open valve that can allow modulation ofthe flow profile through the valve.

In FIG. 1, a gas source 102 is connected to the regulator 162 throughinlet line 166. The regulator 162 is spaced from the fast pulsing valve164 by pressure controller conduit 168. The length and/or volume of thepressure control conduit 168 can be any suitable length and/or volume,respectively. In some embodiments, the length and/or volume of thepressure control conduit 168 is minimized so that the fast pulsing valve164 is in contact with the regulator 162.

Referring to FIG. 1 and FIG. 3, the gas distribution apparatus 100includes a flow controller 170 at each of the downstream ends 112 of theshared volume 110. FIG. 3 shows an expanded view of region III ofFIG. 1. Each flow controller 170 includes an orifice 172 and a fastpulsing valve 174. The orifice 172 can be upstream of the fast pulsingvalve 174, as shown in the Figures. In some embodiments, the orifice 172is downstream of the fast pulsing valve 174.

The orifice 172 is in fluid communication with the fast pulsing valve174 through flow control conduit 176. The volume of the flow controlconduit 176 can be any suitable volume. In some embodiments, the volumebetween the orifice 172 and the fast pulsing valve 174 is minimized sothat the orifice 172 and fast pulsing valve 174 are in contact. In someembodiments, the orifice 172 is at or within the inlet end 173 of thefast pulsing valve 174. In some embodiments, the orifice 172 is at orwithin the outlet end 175 of the fast pulsing valve 174.

The orifice 172 of some embodiments is a disk-shaped component with aprecise aperture 171 extending therethrough. The orifice 172 acts as arestrictor in the flow path. In some embodiments, the gas distributionapparatus 100 includes a downstream gas conduit 180 connected to and influid communication with the downstream end 178 of each flow controller170. The flow rate of gas exiting any of the flow controllers into thedownstream gas conduit 180 is a function of the difference in pressuredownstream of the orifice in the downstream gas conduit from thepressure upstream of the orifice.

In some embodiments, the pressure upstream of the orifices 172 in eachof the flow controllers 170 is substantially the same. As used in thismanner, the term “substantially the same” means that the pressureimmediately before the orifices 172 are within 5%, 4%, 3%, 2% or 1%relative to the average pressure at all orifices 172.

The shared volume 110 of some embodiments is sufficiently large so thatpressure perturbations in each downstream gas conduit 180 is less than±5%, ±4%, ±3%, ±2% or ±1% relative to the average pressure.

Some embodiments of the disclosure are directed to methods ofcalibrating a flow control 170 comprising a fast pulsing valve 174 andan orifice 172. The pressure controller 160 is opened at the upstreamend 111 of the shared volume 110 to pressurize the shared volume 110.Opening the pressure controller 160 can include openings the regulatorand/or openings the fast pulsing valve 164. During pressurization, eachof the flow controllers 170 is closed. After pressurizing the sharedvolume 110, the pressure controller 160 is closed to isolate the sharedvolume.

The pressure of the shared volume 110 can be monitored with the pressurecontroller 160 and flow controller 170 closed while the shared volume110 is pressurized. A drift in the pressure measured using the pressuregauge 150 can indicate a leak in the system.

The pressure in the shared volume 110 is measured as an initialpressure. One of the fast pulsing valves 174 of one of the flowcontrollers 170 is opened and closed a predetermined number of times andthe final pressure of the shared volume is measured. The difference inthe final pressure relative to the initial pressure divided by thenumber of times that the valve was pulsed gives a pressure loss perpulse of that fast pulsing valve 174.

This process can be repeated for each of the flow controllers 170 tocalibrate the pressure drop per pulse of each fast pulsing valve 174.The pulse window for one or more of the fast pulsing valves 174 can bealtered to compensate for differences in the individual orifices 172 andfast pulsing valves 174.

FIG. 4 illustrates another pressure controller 160 connected to theupstream end 111 of the shared volume 110. The illustration showsexpanded view of region II of FIG. 1 according to another embodiment ofthe disclosure. In this embodiment, after the regulator 162 or mass flowcontroller, there are two flow paths 169 a, 169 b for the pressurecontrol conduit 168. Each of the flow paths 169 a, 169 b has a fastpulsing valve 164 a, 164 b, respectively. The separate flow paths 169 a,169 b can be isolated from each other by valves 177 a-d, 177 e-h,respectively to allow for the replacement of the fast pulsing valve 164a, 164 b of one of the flow paths 169 a, 169 b without stopping anyprocess being used. As will be understood by the skilled artisan, thedual valves on either side of the fast pulsing valves can be used toisolate the flow to one of the flow paths.

The gas distribution apparatus 100 of some embodiments further comprisesa controller 190. The controller 190 may be coupled to variouscomponents of the gas distribution apparatus 100 to control theoperation thereof. The controller 190 can be a single controller thatcontrols the apparatus, or multiple controllers that control individualportions of the apparatus. For example, the gas distribution apparatus100 may include separate controllers for each of the pressure controller160 and flow controller 170.

In some embodiments, the controller 190 includes a central processingunit, a memory, and support circuits. The controller 190 may control thegas distribution apparatus 100 directly, or via computers (orcontrollers) associated with particular process chamber and/or supportsystem components. The controller 190 may be one of any form ofgeneral-purpose computer processor that can be used in an industrialsetting for controlling various chambers and sub-processors. The memoryor computer readable medium of the controller may be one or more ofreadily available memory such as random access memory (RAM), read onlymemory (ROM), floppy disk, hard disk, optical storage media (e.g.,compact disc or digital video disc), flash drive, or any other form ofdigital storage, local or remote. The support circuits are coupled tothe CPU 196 for supporting the processor in a conventional manner. Thesecircuits include cache, power supplies, clock circuits, input/outputcircuitry and subsystems, and the like. One or more processes may bestored in the memory as software routine that may be executed or invokedto control the operation of the apparatus or individual components inthe manner described herein. The controller 190 can include one or moreconfigurations which can include any commands or functions to controlflow rates, gas valves, gas sources or other processes for performingthe various configurations.

The controller 190 can be connected to one or more of the pressurecontroller 160, the flow controller 170, the pressure gauge 150, theregulator 162, fast pulsing valve 164 or fast pulsing valve 174. Thecontroller 190 can have one or more configurations. In some embodiments,the controller 190 has a configuration to open and/or close one or moreof the fast pulsing valves 164, 174. In some embodiments, the controller190 has a configuration to monitor pressure using the pressure gauge150. In some embodiments, the controller 190 has a configuration tocontrol regulator 162. In some embodiments, the controller 190 has aconfiguration to calibrate the flow controllers 170.

Some embodiments of the disclosure are directed to processing platform.For example, the embodiment illustrated in FIG. 1 can be considered aprocessing platform with three process chambers (processing stations101). Each process station 101 is connected to one flow controller 170at the downstream end of the shared volume 110 through a downstream gasconduit 180.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A gas distribution apparatus comprising: a sharedvolume having an upstream end and a plurality of downstream ends; apressure gauge connected to the shared volume; a pressure controllerconnected to the upstream end of the shared volume; and a flowcontroller at each of the downstream ends of the shared volume, eachflow controller comprising an orifice and a fast pulsing valve; and acontroller connected to the pressure gauge and each flow controller andconfigured to calibrate at least one of the flow controllers based onfeedback from the pressure gauge before and after opening the at leastone of the flow controllers a predetermined number of times.
 2. The gasdistribution apparatus of claim 1, wherein the shared volume comprises agas reservoir, distribution lines from the gas reservoir to theplurality of downstream ends of the shared volume and distribution linesfrom the upstream end of the shared volume to the gas reservoir.
 3. Thegas distribution apparatus of claim 2, wherein the pressure gauge isconfigured to measure the pressure in the gas reservoir.
 4. The gasdistribution apparatus of claim 1, wherein the pressure controllercomprises one or more of a regulator or mass flow controller.
 5. The gasdistribution apparatus of claim 1, wherein the pressure controllercomprises a fast pulsing valve between a regulator and the sharedvolume.
 6. The gas distribution apparatus of claim 1, further comprisinga downstream gas conduit connected to a downstream end of each flowcontroller.
 7. The gas distribution apparatus of claim 6, wherein theorifice comprises a restrictor to restrict a flow of gas from thedownstream ends.
 8. The gas distribution apparatus of claim 6, whereinthe flow rate of gas exiting any of the flow controllers into thedownstream gas conduit is a function of the difference in pressuredownstream of the orifice in the downstream gas conduit from thepressure upstream of the orifice.
 9. The gas distribution apparatus ofclaim 8, wherein the pressure upstream of the orifices is substantiallythe same for each downstream end of the shared volume.
 10. The gasdistribution apparatus of claim 6, wherein pressure perturbations ineach downstream gas conduit is less than or equal to ±2%.
 11. The gasdistribution apparatus of claim 1, wherein the fast pulsing valve of theflow controller is configured to open or close with 50 milliseconds. 12.The gas distribution apparatus of claim 1, wherein a volume between theorifice and the fast pulsing valve is minimized.
 13. The gasdistribution apparatus of claim 1, wherein the fast pulsing valve of theflow controller is downstream of the orifice.
 14. The gas distributionapparatus of claim 1, wherein the fast pulsing valve of the flowcontroller is upstream of the orifice.
 15. The gas distributionapparatus of claim 1, wherein the controller has one or moreconfigurations selected from a first configuration to control thepressure controller; and a second configuration to open and close thefast pulsing valves of the flow controller on at least one downstreamend of the shared volume.
 16. A processing platform comprising aplurality of processing chambers, each chamber connected to one flowcontroller at the downstream end of the shared volume through adownstream gas conduit of the gas distribution apparatus of claim
 1. 17.A gas distribution apparatus comprising: a shared volume having anupstream distribution line with an upstream end, a gas reservoir and aplurality of downstream distribution lines, each downstream distributionline having a downstream end; a pressure gauge connected to the sharedvolume; a pressure controller connected to the upstream end of theshared volume, the pressure controller comprising a fast pulsing valvebetween a regulator and the shared volume, the fast pulsing valveconfigured to open or close within 50 milliseconds; a flow controller ateach of the downstream ends of the shared volume, each flow controllercomprising an orifice and a fast pulsing valve, the pressure upstream ofeach of the orifices of the flow controllers are substantially the same;a downstream gas conduit connected to and in fluid communication withand downstream of the flow controller; and a controller having one ormore configurations selected from a first configuration to control thepressure controller; a second configuration to open and close the fastpulsing valves of the flow controller on at least one downstream end ofthe shared volume, the controller configured to calibrate at least oneof the flow controllers based on feedback from the pressure gauge beforeand after opening the at least one of the flow controllers apredetermined number of times.
 18. The gas distribution apparatus ofclaim 17, wherein the flow rate of gas exiting any of the flowcontrollers into the downstream gas conduit is a function of thedifference in pressure downstream of the orifice in the downstream gasconduit from the pressure upstream of the orifice.